Over the last several years, low emissivity windows which allow shorwave energy to be transmitted through glass but which reflect long wave (infrared energy) have become very popular in the construction of new buildings. These windows are attractive and can be economically efficient if they are constructed to save a significant amount of money on heating and cooling costs. Due to the reflection of the long wave infrared energy on the outside of the window in the summer season radiant heat cannot get into the building, therefore the window helps to keep cooling costs at a lower level. In the winter season, due to the reflection of the infrared energy on the inside of the window, heat cannot escape as easily and therefore the window can assist in keeping the winter heating costs at a lower level. These low emissivity windows are also efficient for keeping out long wave infrared radiation, however they transmit a relatively high percentage of visible light and solar shortwave infrared radiation, which also can act to heat up a room in the summer season thus increasing cooling costs.
The state of the art is shown by the following cited references:
______________________________________ U.S. Pat. No. Name Date ______________________________________ 4,098,956 Blickensderfer et al 1978 4,180,954 Gell, Jr. 1980 4,462,883 Hart 1984 4,497,700 Groth et al 1985 4,515,151 Slemmons et al 1985 4,548,691 Dietrich et al 1985 4,610,771 Gillery 1986 4,902,580 Gillery 1990 4,902,081 Huffer 1990 4,790,922 Huffer 1988 4,799,745 Meyer et al 1989 4,773,717 Pai et al 1988 4,898,789 Finley 1990 5,059,295 Finley 1991 4,965,121 Young et al 1990 5,085,926 Iida et al 1992 ______________________________________
The disclosures of the above references are hereby incorporated herein by reference.
In the past there have been significant problems in attempting to produce low emissivity low transmission coatings for such glass windows using materials that are readily available. In addition, in the past, there have been significant problems in attempting to produce such low emissivity windows which also provide a low shading coefficient.
Accordingly one object of the present invention is to produce a new low emissivity low shading coefficient glass window.
Another object of the present invention is to provide a new heat reflecting low emissivity window which assists in reducing the heating and air conditioning costs for buildings utilizing such windows.
Another object of the present invention is to provide a new method of manufacturing low emissivity windows.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawing.